Color-plus-clear coating systems involving the application of a colored or pigmented base coat to a substrate followed by the application of a transparent or clear topcoat to the base coat have become conventional as original finishes for automobiles. The color-plus-clear systems have outstanding gloss and distinctness of image.
However, a problem frequently encountered with such systems is poor adhesion between coating layers ("intercoat adhesion"), particularly when a base coat or clear coat layer is applied over another clear coat layer during on-line repairs of original equipment paint jobs, and when a clear coat is applied over an electrocoat layer or a base coat is applied over a clear coat layer during custom two-tone painting. Two-tone painting involves the application of a base coat and clear coat system to an entire automotive part or portion thereof, after which an area is covered or "masked" so that the remaining exposed area can be painted with a different colored base coat followed by a clear coat. In these situations a base coat may be applied on top of a clear coat layer or on top of an electrocoated layer which has clear coat overspray on it.
It would be desirable to provide a color-plus-clear coating system which is useful as an original finish for automobiles and which avoids the intercoat adhesion problems of the prior art systems.